ERVW-1 and HIV-1 infection: Similarly, a mutation in the CA NTD (N74D) has been shown to bypass the need for the nuclear import factor transportin-SR2 in HIV-1 infection [87]; however, the transportin-SR2 independence conferred by the N74D mutation was Env glycoprotein dependent in that VSV-G-pseudotyped N74D virus could infect cells depleted of transportin-SR2 but N74D virus bearing HIV-1 Env could not [88].